Controlling the Interaction Between Carbon Dioxide and Cementitious Materials Using Biomimetic Molecules

这项研究旨在使可持续的基础设施材料，包括补充胶凝材料(SCM)和碱活性材料(AAM)，通过减少这些材料暴露在二氧化碳中时的劣化，使其使用更长时间。这项研究将通过促进对可直接用作二氧化碳汇的胶凝材料的理解和应用，进一步促进低碳未来的发展。这项研究的外展工作包括培养一支由土木工程、材料科学和化学专业的教职员工和学生组成的多学科队伍，以应对为民用基础设施创造可持续和耐用材料的挑战。直接的教育好处包括为本科生和高中生以及代表性不足的群体提供指导研究的机会。这些机会将为学生提供接触先进研究设施的机会，并激励他们在基础设施材料领域继续接受高等教育。这项研究将利用仿生方法来控制原位沉淀碳酸钙颗粒的生长、聚集和特性，以控制胶凝材料和二氧化碳之间的相互作用。具体目标包括：(I)确定原位沉淀的亚稳态碳酸钙(MCaCO3)和碳酸钙-有机杂化(MCOH)相在暴露于外部二氧化碳时避免水化硅酸钙(C-S-H)和水化硅酸铝钙(C-A-S-H)凝胶相降解的有效性，从而提高含有AAM和SCM的水泥基复合材料的抗碳化性能；(Ii)研究如何利用仿生分子在碳化固化基质中沉淀具有可控形貌和性质的特定MCaCO3，以便利用其原位形成的结构来开发高性能胶凝基质；(Iii)研究仿生分子和碳酸钙颗粒的多晶性结晶之间的功能关系，从而开发非天然和负担得起的仿生分子，可用作水泥材料的化学混合物。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

This research aims to make sustainable infrastructure materials, including supplementary cementitious materials (SCMs) and alkali-activated materials (AAM), last longer by reducing their deterioration when these are exposed to carbon dioxide. This research will further contribute to the low-carbon future by advancing the understanding and applications of cementitious materials that can directly serve as carbon dioxide sinks. The outreach effort of this research involves developing a multidisciplinary workforce with faculty members and students from civil engineering, materials science, and chemistry to address the challenges of creating sustainable and durable materials for civil infrastructures. The direct educational benefits include mentored research opportunities for undergraduate and high school students as well as underrepresented groups. These opportunities will provide students with exposure to advanced research facilities and motivate them to pursue higher education in the field of infrastructure materials. This research will capitalize on the biomimetic approaches of engineering the growth, aggregation, and characteristics of in-situ precipitated calcium carbonate particles to control the interaction between cementitious materials and carbon dioxide. The specific objectives include: (i) determining the effectiveness of in-situ precipitated metastable calcium carbonate (mCaCO3) and calcium carbonate-organic hybrid (mCOH) phases to avoid degradation of calcium silicate hydrate (C-S-H) and calcium aluminum silicate hydrate (C-A-S-H) gel phases when exposed to external carbon dioxide, thus enhancing the carbonation resistance of cementitious composites containing AAMs and SCMs; (ii) investigating how biomimetic molecules can be used to precipitate specific mCaCO3 with controlled morphologies and properties in carbonation cured matrices so that their in-situ formations can be leveraged to develop high-performance cementitious matrices; (iii) investigating the functional relationship between biomimetic molecules and the polymorphic crystallization of calcium carbonate particles, and therefore, developing non-natural and affordable biomimetic molecules that can be used as chemical admixtures in cementitious materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.